Background

Obesity, particularly combined with metabolic syndrome (MetS), is associated with reduced quality of life (QOL). This analysis examined the sensitivity of two QOL instruments at detecting the impact of body mass measures and MetS severity on QOL in an obese sample.

Methods

Baseline data from 800 participants with obesity (body mass index [BMI] ≥30.0kg/m2) enrolled in the Promoting Successful Weight Loss in Primary Care in Louisiana (PROPEL) trial were analyzed. Health-related QOL (Patient-Reported Outcomes Measurement Information System [PROMIS]-29) and weight-related QOL (Impact of Weight on Quality of Life-Lite [IWQOL]) were assessed and weight, BMI, and waist circumference (WC) were measured. Further, fasting blood glucose, blood pressure, high-density lipoprotein cholesterol, and triglycerides were measured and a MetS severity z-score was calculated. Pearson correlations were used to assess associations among measures, with a significance level of 0.001 to account for multiple testing.

Results

Modest to medium correlations (r=0.25-0.36) were found between the IWQOL physical function and public distress subscales and weight, BMI, and WC. None of the PROMIS-29 subscales showed correlation coefficients >0.20 with any body mass measure. Despite a medium correlation (r=0.35) between weight and the MetS severity score, no subscales from either QOL instrument had correlations >0.19 with MetS severity.

Conclusions

In a population with obesity, the IWQOL was more sensitive than the PROMIS-29 at detecting weight’s negative association with QOL. While weight sensitivity is expected for the IWQOL due to its item format, it was hypothesized that the PROMIS-29 would be more sensitive than observed as it is recommended for use across different populations. Surprisingly, MetS severity was not related to either QOL instrument, indicating that subjective aspects of QOL are not associated with disease risk severity. This may contribute to unawareness of the progression of disease/disease risk over time.